JP2007132450A - Torque limiting mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the occurrence of a slip in a slip clutch part without using a sensor for measuring a rotating speed. <P>SOLUTION: When the slip is caused in the slip clutch part 3 interposed between an input shaft 1 and an output shaft 2, rotation of the input shaft 1 and rotation of the output shaft 2 become asynchronous, and a phase difference is generated between both. An operation converting part 4 is constituted for converting this phase difference into linear displacement of an actuator 43, and the effect of causing the slip is known by detecting displacement of the actuator 43 by a detecting part 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission system for general industrial machines, aircraft, and the like, and relates to a torque limiting mechanism that can suppress transmission of torque when a torque exceeding a specified level is applied.

A slip clutch (see, for example, the following patent document) is well known as a mechanism that transmits torque from an input shaft to an output shaft and can suppress transmission of torque when a torque exceeding a specified level is applied. The slip clutch transmits torque through friction between a friction plate that is splined to the input shaft and a friction plate that is splined to the output shaft, and is transmitted by slipping the friction plates when excessive torque is applied. Torque is reduced.
JP 2002-031156 A Japanese Patent No. 2756456

  In a machine / equipment in which a slip clutch is interposed between an input shaft and an output shaft, there is a desire to detect the fact at an early stage when a slip occurs. The reason is that, first, when the output shaft does not rotate properly, it is necessary to identify whether the slip in the slip clutch part is caused or whether the input shaft itself is not rotating. Second, the friction plate This is to quickly brake the rotation of the input shaft when the slip is generated in order to keep the frictional heat accompanying the slip between them within a certain limit.

  Conventionally, in order to detect the occurrence of slip, sensors for measuring the rotational speed of the input shaft and the output shaft have been provided to monitor the difference in rotational speed. However, providing such a sensor is costly. The burden was great.

  An object of the present invention made in view of the above is to make it possible to detect the occurrence of slip in the slip clutch portion without using a sensor for measuring the rotational speed.

  In the present invention, a slip clutch portion is provided between the input shaft and the output shaft, and when the input torque exceeding the specified level is applied, the slip clutch portion is slipped to limit the output torque. In the mechanism, an operation converting unit that converts a phase difference generated between the input shaft and the output shaft due to slip of the slip clutch unit into a linear displacement of the actuator, and using the displacement of the actuator And a detecting section for detecting that slip has occurred in the slip clutch section.

  That is, instead of measuring the rotational speeds of the input shaft and the output shaft, the phase difference between the input shaft and the output shaft is converted into a mechanical displacement of the actuator, and the displacement of the actuator is detected. Accordingly, it is possible to detect the occurrence of slip at a relatively low cost without providing a sensor for measuring the rotation speed.

  According to the present invention, the occurrence of slip in the slip clutch portion can be detected without using a sensor for measuring the rotational speed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the torque limiting mechanism of the present embodiment slips between an input shaft (or output shaft) 1 and an output shaft (or input shaft) 2 that are driven to rotate about the same axis A. A torque input to the input shaft 1 is transmitted to the output shaft 2 through the clutch unit 3.

  The slip clutch unit 3 includes a friction plate 31 that is spline-coupled (key-coupled) to the input shaft 1, a friction plate 32 that is spline-coupled to the output shaft 2, and a preload spring 33 that presses the friction plates 31 and 32 in an overlapping manner. It comprises. In the illustrated example, the output shaft 2 is accommodated in the input shaft 1, and the friction plates 31 and 32 are attached so as to alternately overlap the outer periphery of the output shaft 2 and the inner periphery of the input shaft 1 along the axis A direction. ing.

  When torque is input to the input shaft 1, the torque is transmitted to the output shaft 2 through the friction between the friction plates 31 and 32, and the input shaft 1 and the output shaft 2 rotate synchronously. However, when an excessive torque exceeding the specified value is applied, the torque transmitted by slipping between the friction plates 31 and 32 is reduced. When slip occurs, the rotation of the input shaft 1 and the rotation of the output shaft 2 become asynchronous, and a phase difference occurs between them.

  Thus, the phase difference generated between the input shaft 1 and the output shaft 2 due to the slip between the friction plates 31 and 32 is converted into a linear displacement of the actuator 43, and the displacement of the actuator 43 is changed. By detecting this, the fact that a slip has occurred is obtained.

  The motion converter 4 that converts the phase difference between the input shaft 1 and the output shaft 2 into mechanical displacement includes an input side ring 41 provided on the input shaft 1 and an output side ring 42 provided on the output shaft 2 as elements. To do. The input side ring 41 rotates about the axis A together with the input shaft 1, and the output side ring 42 rotates about the axis A together with the output shaft 2. The input side ring 41 and the output side ring 42 are engaged with each other to form a cam. That is, one is a slide ring supported so as to be displaceable in the direction of the axis A, and this slide ring rotates relative to the other cam ring and simultaneously displaces in the direction of the axis A to drive the actuator 43. .

  In this embodiment, the input side ring 41 is a slide ring and the output side ring 42 is a cam ring. The input side ring 41 is splined to the input shaft 1. The output side ring 42 is fixed to the output shaft 2. Further, the output side ring 42 is accommodated in the input side ring 41, and the outer peripheral surface of the output side ring 42 and the inner peripheral surface of the input side ring 41 are arranged to face each other in the radial direction.

  In addition, a cam groove 42a is formed on the outer periphery of the output side ring 42, and a pin 41a engaging with the cam groove 42a is provided on the inner periphery of the slide ring. As shown in FIG. 2, the cam groove 42 a is carved in an annular shape so as to go around the output side ring 42 while gradually changing the position in the direction of the axis A, and is symmetrical to the diameter of the output side ring 42. Yes. Two pins 41a enter the cam groove 42a and slide along the cam groove 42a, and there are two pins 41a so as to face the radial direction of the input side ring 41.

  When slip occurs in the slip clutch portion 3 and a phase difference is generated between the input shaft 1 and the output shaft 2, the input side ring 41 rotates relative to the output side ring 42 around the axis A. At this time, the pin 41a slides along the cam groove 42a, and as a result, the pin 41a and thus the input side ring 41 are displaced in the direction of the axis A. The amount of displacement of the input side ring 41 in the direction of the axis A is relative to the output side ring 42 by the input side ring 41 from the initial installation position (position where no slip is generated in the slip clutch portion 3). It becomes maximum when it is rotated 90 degrees.

  The operating element 43 is supported by the housing 6 so as to be able to project and retract linearly in the direction of the axis A. The input side ring 41 pushes out the actuator 43 to the left in the figure when a slip occurs in the slip clutch portion 3. When the asynchronous rotation of the input shaft 1 and the output shaft 2 continues, the input side ring 41 vibrates in the direction of the axis A, but the actuator 43 is accompanied by a detent mechanism (or moderation mechanism) and is once pushed out. The operating element 43 protruding in this way does not automatically dip into its original position unless operated from the outside. The detent mechanism is a ball that engages with any one of the detent grooves 43a and 43b formed on the outer periphery of the operating element 43 and the detent grooves 43a and 43b to position the operating element 43 in the protruding position or the retracted position and to regulate the protruding and retracting operation. 44 and a spring 45 that elastically urges the ball 44 in a direction intersecting the operating element 43.

  In short, the detection unit 5 that detects that slip has occurred in the slip clutch unit 3 detects an event in which the operating element 43 is pushed out by the input side ring 41 and protrudes. For example, a limit switch 5 that is switched on / off by engagement of a protruding actuator 43 is provided as a detection unit, and the system is automatically stopped when the occurrence of slip is detected via the limit switch 5. Is possible. Incidentally, the protrusion of the actuator 43 can be confirmed visually.

  According to the present embodiment, the slip clutch portion 3 is interposed between the input shaft 1 and the output shaft 2, and when the input torque exceeding the specified level acts, the slip clutch portion 3 is slipped to limit the output torque. In the torque limiting mechanism configured to perform the operation, the phase difference generated between the input shaft 1 and the output shaft 2 due to the slip of the slip clutch portion 3 is converted into a linear displacement of the actuator 43. Since the conversion unit 4 and the detection unit 5 that detects the occurrence of slip in the slip clutch unit 3 using the displacement of the operating element 43 are provided, the rotational speeds of the input shaft 1 and the output shaft 2 are measured. Therefore, it is possible to detect the occurrence of slip at a relatively low cost without using a sensor.

  The present invention is not limited to the embodiment described in detail above. For example, the device constituting the detection unit 5 is not limited to a mechanical switch such as a limit switch, and various sensors (active infrared sensor, distance measuring sensor, optical sensor, etc.) can be used.

  In the above embodiment, the input side ring 41 is splined to the input shaft 1 to form a slide ring, but conversely, the output side ring 42 may be splined to the output shaft 2 to form a slide ring. It is done.

  Further, a cam groove may be formed on the inner periphery of the input side ring 41 and a pin may be provided on the outer periphery of the output side ring 42.

  The cam of the motion converting unit 4 is not limited to the cam formed by the cam groove 42a and the pin 41a, and does not prevent the use of cams in other modes.

  Furthermore, it is also possible to provide a so-called ball lamp to constitute the motion conversion unit. That is, the input side member that rotates together with the input shaft and the output side member that rotates together with the output shaft are made to face each other along the axial direction, and a concave groove having a tapered side end surface is formed on the opposing surface of both members. Then, the ball is clamped between the concave grooves. When a phase difference occurs between the input shaft and the output shaft, the ball rides on the side end surface of the concave groove and tries to escape, thereby separating both members in the axial direction. Therefore, if the input side member or the output side member can be displaced in the axial direction via spline coupling or the like, the phase difference between the input shaft and the output shaft can be converted into a linear displacement.

  Other specific configurations of the respective parts are not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

Sectional drawing which shows the torque limiting mechanism of one Embodiment of this invention. The side view which shows the cam ring and cam groove in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Input shaft 2 ... Output shaft 3 ... Slip clutch part 4 ... Operation | movement conversion part 5 ... Detection part

Claims (1)

In a torque limiting mechanism configured to limit the output torque by slipping the slip clutch part when an input torque exceeding a specified level is provided by providing a slip clutch part between the input shaft and the output shaft,
An operation conversion unit that converts a phase difference generated between the input shaft and the output shaft due to slip of the slip clutch unit into a linear displacement of an actuator;
A torque limiting mechanism, comprising: a detecting unit that detects that slip has occurred in the slip clutch unit by using displacement of the operating element.

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